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Postmortem Changes in Rat Brain Extracellular Opioid Peptides Revealed by Microdialysis
Author(s) -
Maidment Nigel T.,
Siddall Brenda,
Rudolph Veronica D.,
Evans Christopher J.
Publication year - 1991
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1991.tb03456.x
Subject(s) - microdialysis , extracellular , ischemia , chemistry , extracellular fluid , anesthetic , opioid peptide , radioimmunoassay , egta , opioid , pharmacology , anesthesia , medicine , calcium , biochemistry , receptor
Microdialysis combined with a solid‐phase radioimmunoassay was used to monitor changes in extracellular opioid peptide levels in the rat globus pallidus/ventral pallidum as a result of terminal brain ischemia. Ischemia was induced by anesthetic overdose or by severance of blood vessels supplying the brain. In control animals the recovered immunoreactivity increased an average of 13‐fold in the 30‐min sample following anesthetic overdose. Perfusion of a calcium‐free, 10 m M EGTA‐containing medium through the dialysis probe significantly attenuated the amplitude of this response, with the average increase being only threefold. Shorter sampling intervals (5 min) indicated that release of opioid peptide material into the extracellular environment occurs within the first 5 min of ischemia resulting from severance of the blood supply to the brain. HPLC analysis identified the majority of the postmortem‐induced immunoreactive material as Met‐ and Leu‐enkephalin.